INTRODUCTION
Dermal fillers offer a nonsurgical approach for reducing
facial rhytides and restoring facial volume. From 2000
to 2011, there were more than 13 new FDA-approved
injectable fillers.1 In 2013, there were 995,000 soft-tissue filler
procedures in the United States, an increase of 8.6% from 2012.2
Silicones and paraffins were initially used for aesthetic
procedures to restore facial volume and contours, but complications
such as granulomas and paraffinomas years after
treatment have made their use for aesthetic purposes less frequent.
3 The main ingredient of fillers currently available on the
market include hyaluronic acid (HA), poly-L-lactic acid (PLLA),
poly[methyl methacrylate] (PMMA), and calcium hydroxylapatite
(CaHA). HA dermal fillers have become more widely used
by physicians and a favorite for patients due to its immediate,
natural-appearing effects with minimal adverse events and recovery
time.
Characteristics of HA Dermal Fillers
HA, a glycosaminoglycan disaccharide, exists naturally in the body with approximately 50% of total HA is found in the skin and has a half-life of three days or less.4-6 The highly charged nature of HA provides its high solubility and high water binding affinity.7 Currently available HA dermal fillers, depending on its HA concentration, cross-link density, and manufacturing process, has different hydration capacity at equilibrium. This is important considering swelling may be a post-injection complication in some high water binding HA fillers. Previous versions of HA fillers have shown to be safe and efficacious for correction of facial rhytides.1 HA provides the flexibility of being reversible and correctable by using injectable hyaluronidase. A review of currently marketed facial fillers described that many adverse events for HA fillers as mild and transient, and common adverse events include swelling, erythema, and nodules.8
HA, a glycosaminoglycan disaccharide, exists naturally in the body with approximately 50% of total HA is found in the skin and has a half-life of three days or less.4-6 The highly charged nature of HA provides its high solubility and high water binding affinity.7 Currently available HA dermal fillers, depending on its HA concentration, cross-link density, and manufacturing process, has different hydration capacity at equilibrium. This is important considering swelling may be a post-injection complication in some high water binding HA fillers. Previous versions of HA fillers have shown to be safe and efficacious for correction of facial rhytides.1 HA provides the flexibility of being reversible and correctable by using injectable hyaluronidase. A review of currently marketed facial fillers described that many adverse events for HA fillers as mild and transient, and common adverse events include swelling, erythema, and nodules.8
